The sites of acetylation of histone H4 will be identified and their state of modification followed through the cell cycle. Ribosomal chromatin will be isolated from nucleoli and restricted to give transcribed and non-transcribed DNA with their associated proteins. These will be analyzed by 2-D gels and silver staining. Highly acetylated histones will be extracted from butyrate treated cells and fractionated into the different acetylated species. The effect of acetylation on the interactions of histones with DNA will be studied by high resolution nuclear magnetic resonance spectroscopy. HMG proteins 14 and 17 will be isolated and their binding to acetylated core particles and control core particles studied by gel analysis and physical techniques.